Vacuum mixing device with operating element and pump for mixing polymethylmethacrylate bone cement

ABSTRACT

A vacuum mixing device for mixing PMMA bone cement from a monomer liquid and a cement powder, the vacuum mixing device comprising at least one cartridge comprising an evacuable interior for mixing of the bone cement, a mixing device for mixing the content in the interior of the at least one cartridge, which is arranged movably in the interior, a receptacle for receiving a separate container containing the monomer liquid or comprising an integrated container containing the monomer liquid, an opening device, which is arranged in the region of the receptacle in a manner movable relative to the receptacle so that, by moving the opening device, a separate container arranged in the receptacle is openable by means of the opening device, or the opening device is arranged in the region of the integrated container in a manner movable relative to the integrated container so that, by moving the opening device, the integrated container is openable by means of the opening device, a pump, in which a movable plunger for generating a negative pressure is arranged and delimits a pump chamber of the pump, and a connection line, which connects the interior of the at least one cartridge to the pump chamber of the pump, wherein the vacuum mixing system comprises an operating element that is operatable from outside, wherein the plunger in the pump is movable manually by means of the operating element, and wherein the opening device is movable relative to the receptacle or relative to the integrated container by means of the same operating element, and the mixing device in the interior of the cartridge is movable by means of the same operating element in order to mix the content in the interior of the cartridge.

This application claims foreign priority benefit under 35 U.S.C. 119 ofGerman Application No. DE 10 2015 121 274.9 filed Dec. 7, 2015.

FIELD OF THE DISCLOSURE

The invention relates to a vacuum mixing device for the mixing ofpolymethylmethacrylate bone cement (PMMA bone cement) from two startingcomponents, in particular for the mixing of a medical bone cement, andfor storage of the starting components. The invention further relates toa method for the mixing of polymethylmethacrylate bone cement.

Accordingly, the subject matter of the invention is a vacuum mixingdevice for the storage, mixing, and, if applicable, dispensing ofpolymethylmethacrylate bone cement. The invention further relates to amethod for the transferring of monomer liquid into the vacuum mixingdevice and to a method for the mixing of the components ofpolymethylmethacrylate bone cement under vacuum or at negative pressure.

BACKGROUND

Polymethylmethacrylate (PMMA) bone cements are based on the pioneeringwork of Sir Charnley. PMMA bone cements consist of a liquid monomercomponent and a powder component. The monomer component generallycontains the monomer, methylmethacrylate, and an activator(N,N-dimethyl-p-toluidine) dissolved therein. The powder component,which is also referred to as bone cement powder, comprises one or morepolymers, which are produced on the basis of methylmethacrylate andcomonomers, such as styrene, methylacrylate or similar monomers by meansof polymerisation, preferably by suspension polymerisation. The bonecement powder additionally comprises a radiopaquer and the initiatordibenzoylperoxide. During the mixing of powder component and monomercomponent, swelling of the polymers of the powder component in themethylmethacrylate generates a dough that can be shaped plastically andis the actual bone cement. During the mixing of powder component andmonomer component, the activator, N,N-dimethyl-p-toluidine, reacts withdibenzoylperoxide while forming radicals. The radicals thus formedtrigger the radical polymerisation of the methylmethacrylate. Uponadvancing polymerisation of the methylmethacrylate, the viscosity of thecement dough increases until the cement dough solidifies.

Methylmethacrylate is the monomer used most commonly inpolymethylmethacrylate bone cements. Redox initiator systems usuallyconsist of peroxides, accelerators and, if applicable, suitable reducingagents. Radicals are formed only if all ingredients of the redoxinitiator systems interact. For this reason, the ingredients of theredox initiator system in the separate starting components are arrangedappropriately such that these cannot trigger a radical polymerisation.The starting components are stable during storage provided theircomposition is adequate. Only when the two starting components are mixedto produce a cement dough do the ingredients of the redox initiatorsystem, previously stored separately in the two pastes, liquids orpowders, react with each other, forming radicals which trigger theradical polymerisation of the at least one monomer. The radicalpolymerisation then leads to the formation of polymers while consumingthe monomer, as a result of which the cement dough is cured.

PMMA bone cements can be mixed by mixing the cement powder and themonomer liquid in suitable mixing beakers with the aid of spatulas. Onedisadvantage of said procedure is that air inclusions may be present inthe cement dough thus formed and can cause destabilisation of the bonecement later on.

For this reason, it is preferred to mix bone cement powder and monomerliquid in mixing devices with vacuum sources, since mixing in a vacuumremoves air inclusions from the cement dough to a large extent and thusachieves optimal cement quality. Bone cements mixed in a vacuum or atnegative pressure have clearly reduced porosity and thus show improvedmechanical properties. A large number of vacuum cementing systems havebeen disclosed of which the following shall be listed for exemplarypurposes: U.S. Pat. No. 6,033,105 A, U.S. Pat. No. 5,624,184 A, U.S.Pat. No. 4,671,263 A, U.S. Pat. No. 4,973,168 A, U.S. Pat. No. 5,100,241A, WO 99/67015 A1, EP 1 020 167 A2, U.S. Pat. No. 5,586,821 A, EP 1 016452 A2, DE 36 40 279 A1, WO 94/26403 A1, WO 00/35506 A1, EP 1 005 901A2, U.S. Pat. No. 5,344,232 A. In the vacuum cementing systems thusspecified, there is a need to connect an external vacuum pump togenerate the negative pressure. These are generally operated bycompressed air utilising the Venturi principle. The compressed airrequired for operation of the vacuum pumps is supplied either bystationary compressed air facilities or by electrically-operatedcompressors. In addition, it is also feasible to useelectrically-operated vacuum pumps to generate vacuum.

Cementing systems in which both the cement powder and the monomer liquidare already packed in separate compartments of the mixing systems andare mixed with each other in the cementing system only right beforeapplication of the cement, are a development of cementing technology.Such full-prepacked mixing systems were proposed through EP 0 692 229A1, DE 10 2009 031 178 B3, U.S. Pat. No. 5,997,544 A, U.S. Pat. No.6,709,149 B1, DE 698 12 726 T2 and U.S. Pat. No. 5,588,745 A. Saidmixing systems also require an external vacuum source. In this context,the patent DE 10 2009 031 178 B3 discloses a vacuum mixing device havinga two-part dispensing plunger that can also be used for a vacuum mixingdevice according to the invention. Here, a combination of agas-permeable sterilisation plunger and a gas-impermeable sealingplunger is used.

If vacuum mixing devices are used for cementing, external vacuum pumpsneed to be provided. Said vacuum pumps are expensive and need to becleaned after use. Moreover, vacuum hoses for connecting the vacuumpumps to the vacuum mixing devices are required. Said vacuum hoses needto be enclosed with the vacuum mixing devices. Accordingly, prior to themixing using a vacuum mixing device, the vacuum pump needs first to beset up in the operating theatre (OP theatre) and must be connected to anenergy source, such as compressed air, or to an electrical power source.Then, the vacuum pump is connected to the vacuum mixing device by meansof a vacuum hose. Said installation steps take up costly OP time and arepotentially error-prone. The vacuum pump and connecting lines to thevacuum mixing device and to external energy sources and supply linestake up space and constitute potential tripping hazards and obstaclesthat can disturb the often hectic procedure during surgery.

A further interesting concept has been proposed through EP 1 886 647 A1.Here, the cement powder is stored in an evacuated cartridge and themonomer liquid is situated in a separate container. The cartridge, whichis kept at a negative pressure, being opened causes the monomer liquidto be aspirated into the cartridge without any ingress of air. A bonecement dough free of air inclusions is thus produced. Said conceptrequires the cartridge to remain closed in vacuum-tight manner duringthe storage before use such that no non-sterile air can enter into thecartridge. For this purpose, the cartridge must be sealed in a stablehermetic manner. Accordingly, one associated disadvantage is that thedesign is quite elaborate and that the content in the cartridge cannotbe mixed by an externally-operated mixing system after aspiration of themonomer since a feedthrough for a mixing bar or for a mixing tube wouldnot readily be permanently vacuum-tight.

SUMMARY OF THE DISCLOSURE

Accordingly, it is the object of the invention to overcome thedisadvantages of the prior art. Specifically, the disadvantages of theknown vacuum mixing devices as full-prepacked systems having an externalvacuum source are to be overcome without having to maintain a negativepressure over a long period of time. It is the object of the invention,specifically, to develop a vacuum mixing device in which a negativepressure is generated only just before the cement components are beingmixed. The device is to be simplified to the greatest possible extentand is to allow a negative pressure with respect to the surroundingatmosphere to be generated, at least once, in a cement cartridge.Moreover, it can be advantageous that the vacuum mixing device iscapable of enabling a transfer of monomer liquid from a monomercontainer into a cartridge filled with cement powder. Moreover, a methodis then to be provided that enables a monomer transfer and a vacuummixing in full-prepacked mixing devices. Moreover, it is to be possibleto manufacture the vacuum mixing device to be developed mainly frominexpensive plastics material.

A further object of the invention is to develop a simple, closedprepacked mixing device with which polymethylmethacrylate bone cementpowder and monomer liquid can be stored in separate compartments, andthen mixed. It is to be possible to transfer the monomer liquid into thecement powder just before the mixing of the components, without use ofexternal vacuum sources, external electric drives and externalcompressed air drives. With the prepacked mixing device it will bepossible to produce polymethylmethacrylate bone cement purely by manualactuation, independently of additional external devices. Here, themanual actuation is to be simplified to the greatest possible extent.The opening of the monomer ampoule, or monomer ampoules, the monomertransfer, the generation of a vacuum or a negative pressure, and themixing of the cement components is to be caused preferably by a simplemovement, where possible, which has to be repeated particularlypreferably only a few times, for example 3 to 5 times. The use of thevacuum mixing device for the user is thus to be simplified to thegreatest possible extent, such that costly training can be limited orspared. Furthermore, operation of the vacuum mixing device simplified tothe greatest possible extent is intended to minimize potential operatingerrors, thus increasing patient safety.

The polymethylmethacrylate bone cement powder can be combined and mixedwith the monomer liquid within the vacuum mixing device by the medicaluser, without both cement components coming into contact with themedical user. Contact between the medical user and thepolymethylmethacrylate bone cement powder and the monomer liquid must beruled out. The vacuum mixing device to be developed is a full-prepackedvacuum mixing device. The vacuum mixing device is to be designed so thatthe monomer liquid is transferred into the polymethylmethacrylate bonecement powder by vacuum without the use of external vacuum pumps.Furthermore, the vacuum mixing device is to ensure the production ofbone cement dough in a functional and reliable manner without externalenergy sources, such as compressed air, vacuum or electrical current,even under the simplest external conditions. The vacuum mixing device isalso intended particularly preferably to do without an internal energystore, such as batteries or also mechanical energy stores, to thegreatest possible extent. The vacuum mixing device is intended to beusable autonomously, without additional technical equipment.

Moreover, a device that is inexpensive to manufacture and that worksreliably for the mixing of a medical cement and, if applicable, forstorage of the starting components, and a method for the mixing of thebone cement is to be devised, in which the simplest possible manualoperation can be used to mix the starting components, if possiblewithout air inclusions arising in the mixing material.

The main component of the polymethylmethacrylate bone cement, as mixingmaterial, shall be a powder and the second component shall be present inthe form of a liquid. Preferably, it shall be possible to store the twostarting components of the bone cement separately from each other in thevacuum mixing device and to combine them safely through the use of thedevice.

The objects of the invention are achieved by a vacuum mixing device forthe mixing of polymethylmethacrylate bone cement from a monomer liquidand a cement powder, the vacuum mixing device comprising

at least one cartridge comprising an evacuable interior for mixing ofthe bone cement,

a mixing device for mixing the content in the interior of the at leastone cartridge, which mixing device is arranged movably in the interior,

a receptacle for receiving a separate container containing the monomerliquid or comprising an integrated container containing the monomerliquid,

an opening device, which is arranged in the region of the receptacle ina manner movable relative to the receptacle so that, by moving theopening device, a separate container arranged in the receptacle isopenable by means of the opening device, or the opening device isarranged in the region of the integrated container in a manner movablerelative to the integrated container so that, by moving the openingdevice, the integrated container is openable by means of the openingdevice,a pump, in which a movable plunger for generating a negative pressure isarranged and delimits a pump chamber of the pump, anda connection line, which connects the interior of the at least onecartridge to the pump chamber of the pump, whereinthe vacuum mixing device comprises an operating element that isoperatable from outside, wherein the plunger in the pump is movablemanually by means of the operating element, and whereinthe opening device is movable relative to the receptacle or relative tothe integrated container by means of the same operating element, andthe mixing device in the interior of the cartridge is movable by meansof the same operating element in order to mix the content in theinterior of the cartridge.

The vacuum mixing device is preferably also suitable for storing thestarting components of the polymethylmethacrylate bone cement. Themonomer liquid and/or the cement powder are particularly preferablycontained in the vacuum mixing device. The starting components of thepolymethylmethacrylate bone cement are the cement powder and the monomerliquid, wherein the monomer liquid is preferably contained in a glassampoule, which is arranged as a separate container in the receptacle.However, the monomer liquid can also be contained in a film bag asseparate container or can be contained in the integrated container,which is formed by the receptacle or the vacuum mixing device itself.

The term “vacuum mixing device” is not to be understood incorrectly inthe sense that a vacuum is mixed with something, but instead in thesense that the starting components of the bone cement, i.e. the monomerliquid and the cement powder, are mixable under vacuum or under apressure lower than ambient pressure (negative pressure).

The term negative pressure always relates in the present case to apressure relative to the surrounding atmosphere, which pressure istherefore lower than the surrounding atmospheric pressure.

On account of the specific requirements, such as the small volume of theinterior of the cartridge, there is no need for more elaborate pumpsystems.

Provision can be made preferably so that the pump is integrated in thevacuum mixing device. Provision can also be made preferably so that thepressure in the interior of the at least one cartridge can be reduced byat least 50%, preferably can be reduced by at least 90%, by means of thepumping process.

Provision can also be made in accordance with the invention preferablyso that the cement powder is contained in the interior of the cartridge.The cement powder then does not have to be filled into the interior ofthe cartridge.

By coupling the opening device to the operating element, the containerin the receptacle or the integrated container is openable by means ofthe opening device by manually operating the operating element.

In the context of the present invention, the term “evacuable” means thata gas can be removed, i.e. for example a gas can be suctioned from theinterior of the cartridge so that a negative pressure then remains inthe interior of the cartridge. This negative pressure can be used inorder to suck in the monomer liquid.

The vacuum mixing device comprises either a receptacle into which aseparate container, such as a glass ampoule or a film bag, whichcontains the monomer liquid can be inserted, or an integrated containerwhich is formed as an integral part of the vacuum mixing device and inwhich the monomer liquid is already contained.

Provision can also be made so that more than one cartridge is provided,each of which has an interior, wherein a mixing device is then providedin each interior and each interior is connected to the pump chamber ofthe pump or to a corresponding pump chamber of a plurality of separatepumps via a connection line.

The receptacle is also preferably suitable and intended for fixing aglass ampoule or the glass ampoule in the receptacle. The glass ampoulefor this purpose clearly must be shaped appropriately. By way ofexample, the glass ampoule can be plugged into the receptacle by meansof a press fit.

Provision can be made in accordance with the invention so that thereceptacle is closed on one side by means of a lid. Here, at least onegas-permeable opening can preferably be provided in the lid, throughwhich opening gas can flow into the receptacle or can flow in once themonomer liquid is removed from the receptacle. This is intended to avoidthe formation of a negative pressure in the receptacle, which negativepressure counteracts the flow of the monomer liquid into the interior ofthe cartridge.

The cartridge preferably has a pressure-tight feedthrough, through whicha bar, a cable or a mixing shaft is passed, by means of which the mixingdevice is movable from outside the cartridge. For this purpose, the bar,the cable, or the mixing shaft is preferably mounted in the feedthroughrotatably and displaceably in the longitudinal direction. The content inthe cartridge can be well mixed by means of the mixing device.

Preferred embodiments can be characterised in that the vacuum mixingdevice has a total weight less than 10 kg, particularly preferably has atotal weight less than 2 kg, particularly preferably less than 1 kg.

These low weights are possible with the structure according to theinvention of the vacuum mixing device with manually operable operatingelement and the pump. The low weight has the advantage that the vacuummixing device is portable and transportable and usable withoutconnection to supply lines and without great preparation efforts.

Provision can be made in accordance with the invention so that a sieveand/or a filter are/is arranged below the receptacle, the separatecontainer, or below the integrated container so that the content in theopened integrated container or separate container flows through thesieve and/or the filter.

Glass splinters, film snippets, or other residues of the closure or ofthe separate or integrated container created when the separate orintegrated container is opened by means of the opening device can thusbe held back. A clogging of the fluid connection to the interior of thecartridge and a contamination of the bone cement to be produced is thusprevented.

Vacuum mixing devices according to the invention are characterised inthat they do without an electric drive. Provision can thus be made inaccordance with the invention so that the vacuum mixing device does nothave an electric drive or at least the pump, the opening device and themixing device are not driven by means of an electric drive. Instead,these component parts are driven in accordance with the invention viathe manually operable operating element. Vacuum mixing devices accordingto the invention can also be constructed without electronics orelectronic component parts. A vacuum mixing device according to theinvention can thus also be characterised in that no electronics areinstalled therein or no electronics or electronic component parts areused at least in order to drive the pump, the opening device, and themixing device. Electric motors or compressors therefore are not requiredin order to construct vacuum mixing devices according to the invention.

Furthermore, provision can be made in accordance with the invention sothat the vacuum mixing device does not have any energy stores, inparticular no electrical energy stores, such as a primary battery or arechargeable battery, and no compressed gas store, such as a CO₂compressed gas cartridge, or so that at least no energy stores,preferably no electrical energy stores or compressed gas stores, areused in order to drive the pump, the opening device, and the mixingdevice. The vacuum mixing device, however, preferably also does not haveany resilient energy stores, such as tensioned springs.

In the case of vacuum mixing devices according to the invention,provision can be made so that the operating element is connected orconnectable to the plunger in such a way that the plunger is movablemanually in the pump by operation of the operating element.

As a result of this, the plunger is movable, in particular directly, bymeans of the operating element. Here, provision can be made so that theplunger is connected to the operating element only after a firstoperation of the operating element, in such a way that the plunger inthe pump is moved by a further operation of the operating element. Here,a lever is particularly well suited for the embodiment of the operatingelement, which lever can be pulled or pushed or pivoted back and forthabout an axis so that the separate container in the receptacle or theintegrated container is opened after a first movement of the lever andin so doing the plunger and/or the mixing device are/is connected to theoperating element in such a way that the plunger in the pump and/or themixing device in the interior of the cartridge are/is moved in the eventof a reverse movement of the lever. In addition, large forces can betransferred manually into the vacuum mixing device without difficulty bymeans of a lever.

Furthermore, provision can be made so that the receptacle, at least inregions, has closed side walls for receiving a glass ampoule as separatecontainer, wherein the receptacle has at least one deformable closedside wall and a supporting element is provided opposite the deformableside wall, wherein the opening device is pressable via the operatingelement against the deformable side wall of the receptacle so that thedeformable side wall deforms in such a way that a matching glass ampoulearranged in the receptacle can be broken open by means of the openingdevice.

As a result of this measure, the receptacle can be largely closedoutwardly. In addition, it can be ensured as a result that a glassampoule can also be opened within the closed receptacle without furthermonomer liquid being able to escape from the vacuum mixing device,whereby the risk of contamination of the surroundings of the vacuummixing device with the content in the cartridge, in particular with themonomer liquid, can be ruled out or the risk of this is at leastsignificantly reduced.

With a development of the present invention it is proposed for theopening device to have a first lever which is mounted rotatably about afirst axis in relation to the receptacle or the integrated container,wherein a free end of the first lever is pushable against a deformableside wall of the receptacle or the integrated container, wherein theoperating element is formed by a second lever which is mounted pivotablyabout a second axis in relation to receptacle or the integratedcontainer, wherein the second axis divides the second lever into a shortlever arm and a long lever arm, wherein an end of the short lever arm isto be pushed by manual operation of the long lever arm against the firstlever so that the free end of the first lever pushes against thedeformable side wall and deforms this in such a way that a separatecontainer disposed in the receptacle is openable, or pushes the free endof the first lever against the integrated container so that theintegrated container opens towards a fluid connection.

Here, provision can be made so that the separate container is a glassampoule which matches the receptacle and which can be broken open by thepressure of the free end of the first lever or is a film bag which isarranged in the receptacle and which can be pierced or slit open or tornopen by the pressure of the free end of the first lever.

Provision can also be made in such embodiments so that an edge isarranged at the free end of the first lever on the side facing towardsthe receptacle. The length ratio of the long lever arm to the shortlever arm is preferably at least 5 to 1. Furthermore, provision can bemade so that the second lever is to be rotated in the same plane as thefirst lever, wherein the movement of the second lever engages in themovement of the first lever. Provision can also be made preferably sothat the second axis of the second lever is arranged above the firstaxis of the first lever, wherein the first axis of the first lever andthe second axis of the second lever are preferably arranged parallel toone another.

With vacuum mixing devices of this type with glass ampoule, it ispossible to break open a glass ampoule over a large area within thedevice or the cementing device, such that the monomer liquid flows outfrom the glass ampoule within a short period of time and is madeavailable for mixing with the medical bone cement powder. With the aidof the two levers, which interact with one another, it is possible todirect the pressure on the glass ampoule in the direction in which theglass ampoule sits in the receptacle so that the glass ampoule cannotescape from the receptacle. At the same time, a very accurately definedlocal pressure can be exerted onto the glass ampoule, by means of whichthe glass ampoule in the vacuum mixing device can be broken open. Withthe aid of the deformable side wall, is possible to ensure that theforce is transferred through this side wall into the interior of thereceptacle and onto the glass ampoule, wherein the receptacle remainsclosed. An escape of the monomer liquid from the receptacle can thus beruled out. With the aid of the sieve and/or the filter, glass splinterspossibly created as the glass ampoule is opened can be held back. Themonomer liquid can then be used for mixing with the bone cement powder.

The particular advantage of the device according to the invention alsolies in the fact that any glass ampoules, regardless of the ampoulelength and the geometry of the ampoule head, can be safely opened whenthe ampoule diameter is equal to or slightly greater than the innerdiameter of the ampoule holder or the receptacle. It is also aparticular advantage that when breaking the ampoule wall in the regionof the ampoule base, the liquid contained in the glass ampouleimmediately flows out completely, independently of the surface tension.By contrast, in the case of conventional ampoule breakers, the liquidflows out through the relatively narrow cross-section of the ampouleneck, after separation of the ampoule head, significantly more slowly.Here, reasonably high outflow speeds are attained only when thecross-section of the ampoule neck is large enough so that the surfacetension of the liquid cannot hold the meniscus of the liquid in theampoule neck.

The receptacle is preferably a hollow cylinder. The receptacle likewisepreferably consists of an elastomer or comprises an insert made of anelastomer, such as an ethylene propylene diene (EPDM) rubber.

Provision can also be made here so that a shoulder for supporting theglass ampoule is arranged in the receptacle, wherein the shoulder issmaller than half the area of the ampoule base or the ampoulecross-section. Here, provision can in turn be made preferably so thatthe shoulder is arranged in the receptacle in such a way that thedistance between the shoulder and a sieve and/or filter arranged therebelow is the same size as or greater than the outer diameter of theglass ampoule to be inserted.

With a vacuum mixing device that can be provided particularly easily andeconomically, it is proposed for the operating element to be manuallymovable, preferably to be a lever pivotable about an axis, wherein theoperating element is operatively connected to or is to be brought intooperative connection with the opening device, the pump, and the mixingdevice in such a way that with a first operation of the operatingelement a separate container in the receptacle or the integratedcontainer is to be opened, and with a further operation of the operatingelement the plunger in the pump is to be driven, and the mixing devicein the interior is to be driven.

A force which is to be applied manually and which acts on the operatingelement, in particular the lever, can hereby be used in order to firstlyopen the separate or integrated container and then drive or move thepump and the mixing device by means of the same operating element.Levers as operating elements are particularly well suited fortransferring manual force into the vacuum mixing device. This is alsothe case because it is possible to increase the usable force via thelength of the lever arm.

Here, provision can be made so that the plunger of the pump, and/or themixing device are/is to be driven via a flexible cable and/or a rod,wherein a detent means is provided on the flexible cable and/or the rodand after first-time operation of the operating element engages with amating detent means on the operating element or with a mating detentmeans connected to the operating element so that, with operation of theoperating element subsequent to the latching, the plunger of the pumpand/or the mixing device are/is to be driven via the cable and/or therod by means of the operating element.

The force can thus be transferred from the operating element to theplunger and/or the mixing device. The flexible cables are particularlywell suited for the transfer of force, since the direction of the forcecan be deflected therewith without complex mechanics. The flexible cableis preferably sufficiently stiff or rigid so that the plunger and/orparticularly the mixing device can be moved back and forth in bothdirections. The cable can be guided and/or supported for this purpose.By way of example, the cable for this purpose can be guided in achannel, or can be supported and/or deflected at suitable points by ahousing and by struts and/or deflection rollers in the housing. Due tothe use of the detent means and the mating detent means, it is possibleto ensure that the separate container in the receptacle or theintegrated container is firstly opened and the monomer liquid runs outcompletely, before the pump or the plunger of the pump and/or the mixingdevice is operated. By way of example, it is thus possible to preventthe pump from being operated before the monomer liquid is available.

Is also proposed for the mixing device to be axially movable in theinterior in the longitudinal direction by operation of the operatingelement.

A very comprehensive mixing of the interior is hereby achieved inparticular for a cylindrical interior. At the same time, the mixingdevice can be constructed in a compact manner, since it does not have toextend along the entire length of the interior.

Provision can also be made preferably so that the mixing device isrotatable about the longitudinal axis of the interior by operation ofthe operating element in the interior, wherein preferably for thispurpose a cylinder connected to the mixing device and having an externalthread moves in a stationary sleeve having a matching internal thread sothat, when the cylinder moves along the longitudinal direction withinthe sleeve, a rotation of the cylinder is enforced, wherein the rotationof the cylinder transfers to the mixing device in the interior of thecartridge.

An even more thorough mixing of the content in the interior is achievedhereby. Bone cement clinging to the wall of the interior can also beeffectively mixed as a result. The bone cement is thus mixed morequickly and more effectively.

With a development of the present invention provision can also be madeso that the pump chamber of the pump is gas-tight and is arranged in theinterior of the pump, wherein the plunger is manually drivable via theoperating element in at least one direction, such that the pump chamberis to be enlarged by the movement of the plunger and the interior of theat least one cartridge is to be evacuable through the connection line bymeans of the resultant negative pressure created in the pump chamber.

A particularly good pumping effect of the pump is hereby achieved, andtherefore the vacuum that can be generated in the interior of thecartridge is improved. The plunger with the operating element canparticularly preferably be moved manually repeatedly in two directionsalong the axis of the pump chamber so that a repeated pumping in orderto evacuate the interior of the cartridge is possible.

Here, provision can be made so that the volume increase of the pumpchamber is at least as large as the free volume of the interior of thecartridge, and the volume increase of the pump chamber is preferably atleast as large as the sum of the volume of the interior of the cartridgein which the cement powder of the PMMA bone cement is contained, and thevolume of the connection line, and the volume of a fluid connectionbetween the interior of the cartridge and the receptacle for theseparate container or the integrated container, and the volume of amonomer liquid to be mixed with the cement powder of the PMMA bonecement in the cartridge.

It is thus ensured that the pump can evacuate the interior of thecartridge with just one stroke or with few strokes of the plunger. Here,the volume of the pump chamber prior to the pumping process is ideallyas small as possible. Provision can thus be made preferably so that thevolume of the pump chamber after the pumping process is at least 10times greater than the volume of the pump chamber prior to the pumpingprocess, particularly preferably is at least 20 times greater than thevolume of the pump chamber prior to the pumping process. The plungerpreferably does not bear tightly in an areally flush manner against theinterior of the pump, in particular the top surface of a hollow cylindercomprising the connector for the connection line, such that the plungerarea is not fixedly sucked against this area such that it can only bemoved with difficulty in order to start the movement. For this purpose,spacers can be provided on the top surface in the pump chamber and/or onthe plunger in the pump chamber.

In order to be able to operate the pump with a number of actuations ofthe actuating element, or so as to be able to utilise a multiple strokeof the plunger of the pump, provision can be made so that a firstone-way valve is arranged in the connection from the pump chamber to theconnection line or in the connection line, which first one-way valve isopen or is actively opened when a pressure lower than in the interior ofthe cartridge prevails in the pump chamber and is in a closed state oris actively closed when a pressure equal to or higher than in theinterior of the cartridge prevails in the pump chamber, and a secondone-way valve preferably connects the pump chamber to the surroundingsof the pump, which second one-way valve is open or is actively openedwhen a pressure higher than in the surroundings of the pump prevails inthe pump chamber and is in the closed state or is actively closed when apressure equal to or lower than in the surroundings of the pump prevailsin the pump chamber, wherein the one-way valves are preferably checkvalves.

With the first one-way valve, a flow is possible from the interior ofthe cartridge into the pump chamber, but flows in the opposite directionare largely prevented. As a result of the second one-way valve, anoverpressure in the pump chamber can be relieved via the second one-wayvalve.

A particularly good vacuum or a particularly good negative pressure inthe interior of the cartridge can be generated hereby with repeatedpumping by multiple movement of the plunger and can be maintained orimproved further during the mixing process as well.

Furthermore, provision can be made so that the plunger is mountedaxially movably in a hollow cylinder, wherein the hollow cylinder isclosed on a first side or is closed apart from a feedthrough for a rodor cable connected to the operating element and the plunger, inparticular is closed by a closure, wherein a pump chamber is preferablyformed in the hollow cylinder between the plunger and the first closedside, wherein the hollow cylinder is particularly preferably open on asecond side.

The pump chamber and the plunger preferably have a cylindrical geometry.As a result of these measures and also as a result of the cylindricalgeometry, a combined pump that is particularly easily and inexpensivelymanufactured is proposed, which is easily operated and is particularlyunsusceptible to malfunctions.

It is also proposed that the plunger is connected or connectable to theoperating element via a rod and/or a cable, and preferably for theplunger to be moved in the pump by operation of the operating element.

A particularly simple vacuum mixing device is hereby provided, withwhich there is no risk of possible interruptions. The direct connectionof the operating element to the plunger via the cable and/or the rod canbe provided with a one-part injection-moulded part made of plasticsmaterial. Alternatively, a transmission or a gearing can also beprovided, by means of which the force exerted onto the operating elementis transmitted to the plunger in order to enable a more powerfulmovement of the plunger.

In a further development of the vacuum mixing device, provision can bemade so that a movable dispensing plunger for dispensing the mixed bonecement from the cartridge is arranged in the interior of the cartridge,wherein the dispensing plunger is preferably releasably locked orlockable in order to prevent a movement of the dispensing plunger underthe action of the negative pressure.

The operation of the vacuum mixing device is simplified by thedispensing plunger.

Here, provision can be made so that the dispensing plunger has a passagewith a gas-permeable pore plate, which is impermeable for cement powder,wherein the passage with the pore plate connects the interior of thecartridge to the connection line and/or the surroundings in agas-permeable manner, wherein the passage is closable in a gas-tightmanner, preferably is closable in a gas-tight manner by means of asealing plunger of the dispensing plunger.

With the pore plate it is possible to ensure that the interior of thecartridge with the cement powder therein can be sterilised with the aidof a gas, such as ethylene oxide, without there being any risk that thecement powder will pass from the interior of the cartridge externallyinto the surroundings.

Provision can also be made preferably so that the cartridge is a cementcartridge filled with cement powder and a separate container containinga monomer liquid is arranged in the receptacle or a monomer liquid iscontained in the integrated container, wherein the receptacle or theintegrated container is preferably connected in a liquid-impermeablemanner to the interior of the cement cartridge and/or the interior ofthe cement cartridge is connected or connectable in a gas-permeablemanner to the pump.

The monomer liquid can thus be transferred from the separate orintegrated container into the interior of the cartridge by means of thesame pumping movement or the same pumping process by means of which theinterior of the cartridge is evacuated. The vacuum or the negativepressure generated manually by the pump is used here at the same time tosuck the monomer liquid into the cartridge. In particular, theseparating element to be opened is openable in accordance with theinvention by means of the operating element, preferably once theintegrated container or the separate container has been opened.

Provision can also be made so that the cartridge, the pump, and alllines and also the receptacle or the integrated container are fixedlyand/or releasably connected to a common base part and/or a housing,wherein the pump and all lines as well as the receptacle or the separatecontainer are preferably fixedly connected to the base part and/or thehousing, and the cartridge is releasably connected to the base partand/or the housing.

A vacuum mixing device of this type can be easily placed and can beeasily operated. The use of the vacuum mixing device is thus simplified.Merely a flat substrate for setting up the vacuum mixing device must beprovided at the site of use, which in most OP areas does not pose anyproblems.

In accordance with one embodiment provision can be made so that theseparate container containing the monomer liquid is a film bag which canbe cut open or torn open in the receptacle by means of the openingdevice, or is a glass ampoule which can be broken open in the receptacleby means of the opening device.

Commercially available packaging options for the monomer liquid can thusbe used, without having to open these outside the vacuum mixing device.

It is proposed for the receptacle or the integrated container to beconnected or connectable via a fluid connection to the interior of thecartridge, wherein the mouth of the fluid connection into the interiorof the cartridge is preferably arranged on the opposite side of themouth of the connection line between the interior and the pump chamber.

As a result, the monomer liquid can be conveyed via a dedicated line(the fluid connection) into the interior of the cartridge.

Here, provision can be made so that a loop is arranged in the fluidconnection, such that the monomer liquid running out from the openedseparate container or the integrated container cannot flow into theinterior of the cartridge without negative pressure in the interior ofthe cartridge, wherein a storage volume for receiving the liquid volumeof the monomer liquid is preferably arranged below the receptacle or theintegrated container.

With correct placement of the vacuum mixing device, it is thus possibleto ensure that the monomer liquid cannot flow unintentionally into thecartridge without influence of the negative pressure and cannot curethere unintentionally. It is thus possible to prevent the monomer liquidfrom passing into the interior of the cartridge through the liquid linealready when the separate or integrated container (for example themonomer glass ampoule) is opened. This loop, which for example can beconstructed by a reversed U-shaped loop of the fluid connection, meansthat, before any movement of the plunger of the pump, the monomer liquidremains within the vacuum mixing device until at the height of the apexin the fluid connection, whereby a premature entry of the monomer liquidto the cement powder is prevented, wherein in particular in the case ofhighly viscous cements a premature contact of even small volumes of themonomer liquid with the cement powder can lead to a clogging of thefluid connection or a fluid connection formed as a nozzle, as describedin U.S. Pat. No. 8,662,736 B2. The fluid connection can be transparentor translucent so that the user can visually monitor the monomertransfer. For this purpose, a viewing window can be provided in thevacuum mixing device, through which window the loop with the highestapex can be seen.

With a development of the present invention, it is also proposed for anegative pressure to be generated in the pump chamber as a result of themovement of the plunger in the pump, wherein a gas is evacuable throughthe connection line from the interior of the at least one cartridge bymeans of the negative pressure.

A particularly simple and unsusceptible design is hereby provided.

Provision can also be made in accordance with the invention so that thepump is constructed with a hollow cylinder, wherein the hollow cylinderis connected or connectable at the first and at the second hollowcylinder end to the interior of the cartridge, a gas-tight closure atone cylinder end, the plunger, which is arranged in the hollow cylinderin a gas-tight and axially movable manner, wherein the plunger in thepump is movable by means of the manually operable operating element,wherein, with a movement of the plunger by means of the manuallyoperable operating element, the plunger is movable axially oppositely tothe closure and gas can thus be evacuated from the interior of thecartridge, wherein the operating element is operatively connected to theopening device, and wherein the operating element is connected to themixing device in the interior of the cartridge in such a way that themixing device in the interior of the cartridge is movable with operationof the operating element.

This design is particularly simple, and the parts essential for it canbe manufactured from plastics material by injection moulding.

With a particularly preferred embodiment of the present invention,provision can be made so that the pump, the opening device, and themixing device are drivable via the movement of the operating element,wherein the operating element is preferably moved by the action ofmanual force.

The vacuum mixing device therefore does not require any energy stores orany electric or electronic drives. This is desirable since the vacuummixing device is intended for one-time use and in this way can berecycled more easily. In addition, the vacuum mixing device is ready foruse in principle, and does not require any connections, such as cablesor compressed gas tubes, in order to be used.

The objects forming the basis of the present invention are also achievedby a method for mixing polymethylmethacrylate bone cement in an interiorof a cartridge of a vacuum mixing device, in particular a vacuum mixingdevice of the type described above, in which method

an operating element is operated and an integrated container of thevacuum mixing device or a separate container, which is arranged in areceptacle of the vacuum mixing device, is thus opened, wherein amonomer liquid contained in the integrated container or the separatecontainer then runs out as first component of the bone cement,by means of a subsequent, further operation of the operating element, amovement of a plunger of a pump of the vacuum mixing device is driven,wherein a negative pressure is generated in a pump chamber of the pumpby means of the movement of the plunger, wherein the interior of thecartridge is evacuated by means of the pump driven in this way and themonomer liquid is conducted into the interior of the cartridge by meansof the negative pressure in the interior of the cartridge, wherein abone cement powder as second component of the bone cement is alreadydisposed in the interior of the cartridge, anda mixing device in the interior of the cartridge is moved as a result ofthe operation of the operating element and a bone cement dough in theinterior of the cartridge formed from cement powder and the monomerliquid is mixed as a result of the movement of the mixing device.

Here, provision can be made so that the volume of a pump chamber of thepump is increased by the manual movement of the plunger and the interiorof the cartridge is evacuated due to the negative pressure created as aresult.

The pump can thus be provided in a simple way.

Provision can also be made in accordance with the invention so that acement powder is contained in the interior of the cartridge and a gas isevacuated from the interior of the cartridge by means of the pump, amonomer liquid is introduced into the interior of the cartridge, and themonomer liquid is mixed with the cement powder in the evacuated interiorof the cartridge due to a movement of the mixing device.

A design that can be provided particularly easily and reliably can beachieved as a result of the specified combination and interaction of themethod steps.

Furthermore, provision can be made so that the plunger of the pump ismoved by means of the operating element, whereby a negative pressurerelative to the surrounding atmosphere is generated in the pump, in sodoing gas from the interior of the cartridge is sucked into the pumpchamber of the pump through a connection line, and the pump plunger ofthe pump is moved by means of the operating element, whereby a pressureis exerted onto the monomer liquid in the pump chamber, the monomerliquid is pushed through a fluid connection from the pump chamber intothe interior of the cartridge, the vacuum mixing device in the interiorof the cartridge is then moved by operation of the same operatingelement, and in so doing the cement powder is mixed with the monomerliquid, the cartridge containing the mixed cement dough is removed, andthe cement dough is pressed out from the cartridge by means of an axialmovement of a dispensing plunger.

The method is hereby enhanced such that, at the end, a cement cartridgecontaining a bone cement dough mixed under vacuum is provided and can beused immediately.

Lastly, provision can also be made so that the cement powder is arrangedin the cartridge, the monomer liquid is arranged in a receptacleseparate from the cartridge, wherein the monomer liquid is contained inan integrated container or in a separate container, preferably in aglass ampoule in the receptacle, the integrated container or theseparate container is opened by operation of the operating element and aresultant movement of the opening device, before the plunger is drivenby a further operation of the operating element, the plunger is thenmoved axially in a hollow cylinder, whereby a negative pressure comparedto the surrounding atmosphere is generated, in so doing gas from theinterior of the cartridge is sucked through the connection line into thehollow cylinder, and monomer liquid is sucked into the cartridge bymeans of the negative pressure formed in the interior of the cartridge.

The method is thus further enhanced.

Methods according to the invention can also be characterised by theintended application or use of component parts of vacuum mixing devicesaccording to the invention.

The invention is based on the surprising finding that it is possiblewith a single operating element to operate or drive the pump and themixing device and also to operate the opening device. This has theadvantage that there is no need for any complicated handlinginstructions for the operating individual. All sequences can becontrolled and driven by operation of the sole operating element. Thevacuum mixing device is thus simplified to the greatest possible extent.At the same time, there is no need for any energy stores for the drive,and there is no need for any electrical or electronic control unit inorder to drive and control the pump, the mixing device and the openingdevice.

At the same time, it is possible with the aid of the pump, which is tobe driven manually, to provide a vacuum mixing device that isindependent of internal and external power sources and other supplylines. The vacuum mixing device according to the invention can beconstructed in a compact, simple and space-saving manner. The pump, theopening device, and the entire vacuum mixing device can be constructedusing the simplest means, such that the entire vacuum mixing device canbe used as a disposable system. The pump can also be used and inaccordance with the invention preferably is also used to transfer amonomer liquid into the cement powder. The two components of the PMMAbone cement can then be mixed in the vacuum or in the negative pressure.

A device for generating a vacuum or for generating a negative pressureis contained in the cementing systems according to the present inventionand is suitable for the temporary generation of a negative pressurebefore and during the mixing of a powdered component with a liquidmonomer component of the polymethylmethacrylate bone cement.

The idea forming the basis of the invention is based on the finding thatonly a relatively small amount of energy and therefore a low manualapplication of force is necessary in order to open the container for themonomer liquid in order to generate the vacuum or the negative pressurein a cartridge, which is necessary in order to mix the startingcomponents of a bone cement under the negative pressure or the vacuum,and in order to move the mixing device for mixing the bone cement doughin the interior of the cartridge. The amount of energy in order totransfer the monomer liquid into the cement powder is also small. Thissmall amount of energy can be applied readily by operation of a lever asoperating element. The vacuum mixing device hereby can be handled in asimple manner and is easily operated and is also independent of internaland external energy stores. Due to a suitable structure, the order ofthe sequences can also be controlled, specifically the monomer containeris openable first and only then can the pump and the mixing device bedriven.

The idea of the invention is also based on the fact that a negativepressure is generated in a hollow cylinder of the pump by manualactuation of an operating element with a plunger connected thereto in ahollow cylinder of the pump, wherein the negative pressure spreads via aline means into the cartridge and the monomer liquid is sucked from anopened monomer liquid container into the cartridge, in which cementpowder is disposed. The cement components are then mixed manually withthe aid of a mixing device, which is to be driven simultaneously via thesame operating element.

By way of example, the invention can be implemented by means of thefollowing method, in which the following functions are performed in themixing device by activation with a manually operated lever or moregenerally a manually operated operating element:

1^(st) step: actuation of the manual lever or operating element andbreaking of the ampoule or ampoules, leakage of the monomer liquidwithin 1 to 2 seconds into a reservoir, which is connected to a linemeans and a nozzle, wherein the nozzle points via its opening into theinterior of the cartridge; latching of a resilient rod into a matingdetent means of the lever at the stop point of the lever, wherein therod is forked into a first part and a second part;

2^(nd) step: return movement of the manual lever or operating elementinto the starting position, wherein a plunger in a hollow cylinder ismoved axially by the first part of the resilient rod and a negativepressure is created behind the plunger in the hollow cylinder;forwarding of the negative pressure via a check valve and a line meansfor vacuum connection into the interior of the cartridge; creation of anegative pressure in the interior of the cartridge; suctioning of themonomer liquid from the reservoir into the cartridge; movement of thesecond part of the resilient rod, which is rotatably connected to afirst sleeve, which has at least one outermost lobe, which is arrangedmovably in a steep thread of a second sleeve, such that a resilientstirring bar (as mixing shaft) is fixedly connected to the first sleeveso that the first sleeve is rotated by engagement of the lobe in thesteep thread in the event of an axial movement of the first sleevethrough the (or in the) second sleeve, whereby the stirring bar rotatesand moves axially in the cartridge;

3^(rd) step: further actuation of the manual lever or operating element;movement of the first sleeve in the second sleeve; axial movement of thestirring bar in the cartridge with rotation about the longitudinal axis;

4^(th) step: repetition of the 2^(nd) and 3^(rd) steps until the cementdough is homogeneously mixed;

5^(th) step: release of the cartridge or cartridge system by unscrewingand removal of the mixing bar (of the mixing shaft) with the mixingelement; and collapsing of the mixing elements (the mixing blades of themixing device).

The key advantage of the invention is that a prepacked mixing system isproposed which can be used in the simplest manner possible, withoutspecific training measures, by the medical user by means of simplemanual actuation in order to produce a polymethylmethacrylate bonecement dough within a few seconds (for example within 40 seconds). It isalso advantageous that use errors are minimised on account of themaximally simplified operation, thus resulting in an improvement inpatient safety.

The vacuum mixing device according to the invention can be providedsubstantially inexpensively using simple plastics material parts to beproduced by plastics material injection moulding. The particularadvantage of the device according to the invention lies in the fact thatthe device can be operated without external aids, such as vacuum pumpsand vacuum tubes driven by compressed air, and without energy sources,such as compressed air or batteries. The vacuum mixing device accordingto the invention can be used autonomously and can be used even under thesimplest or most difficult operation conditions. A closed full-prepackedvacuum cementing system for price-sensitive markets is provided by meansof the vacuum mixing device according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further exemplary embodiments of the invention will be explainedhereinafter on the basis of eight schematically illustrated Figures,without, however, intending to limit the invention hereto. In theFigures:

FIG. 1: shows a schematic perspective view of a vacuum mixing deviceaccording to the invention;

FIG. 2: shows a schematic perspective view of the vacuum mixing deviceaccording to FIG. 1 with open housing;

FIG. 3: shows a schematic perspective cross-sectional view of the vacuummixing device according to FIGS. 1 and 2 in the starting state;

FIG. 4: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 3 in the starting state;

FIG. 5: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 4 with a plane of section perpendicularto the section of FIGS. 3 and 4;

FIG. 6: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 5 during the operation with broken-openglass ampoule;

FIG. 7: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 6 during the operation with latched cableor latched rod; and

FIG. 8: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 7 during the operation at the time ofpumping and mixing.

DETAILED DESCRIPTION OF THE DISCLOSURE

FIGS. 1 to 8 show various views of a vacuum mixing device according tothe invention before and during operation. The vacuum mixing deviceconsists fundamentally of five parts, specifically a cartridge system 1,a liquid container 2, a pump 3, which is to be driven manually, anoperating element 4, and an opening device 5.

A central part of the cartridge system 1 is a cartridge 6 having acylindrical interior which is closed at its upper side by a two-partdispensing plunger 8 which is arranged movably in a longitudinaldirection in the cylindrical interior of the cartridge 6. The cartridge6 thus has a cylindrical interior with circular base area. The cartridge6 contains a cement powder 9 as starting component for a bone cement.

A mixing device 10 having two or more mixing blades 10 is also arrangedin the interior of the cartridge 6, wherein the mixing device 10 ismounted rotatably and displaceably in the longitudinal direction in theinterior of the cartridge 6 and is secured to a mixing shaft 12 or to acable 12, which is guided rotatably and displaceably in the longitudinaldirection through a feedthrough in the underside of the cartridge 6 intothe interior of the cartridge 6. The feedthrough is pressure-tight andgas-tight for this purpose. The mixing shaft 12 can also be embodied asa flexible rod 12.

The cartridge system 1 is connected to the liquid container 2 and thepump 3 via a base part 18 and a housing 19. The liquid container 2, thepump 3, part of the operating element 4, and the opening device 5 aresurrounded by the housing 19, wherein part of the operating element 4protrudes from the housing 19, whereas the cartridge system 1 is screwedonto the housing 19. The cartridge 6 ends at its underside in aconnection piece having an internal thread 14, which is screwed onto anexternal thread 16 on a connection piece of the housing 19. The basepart 18 here forms the stand 18 of the compact vacuum mixing device. Thecartridge 6 is thus releasable from the housing 19 and therefore therest of the vacuum mixing device. When the bone cement 96 (see FIG. 8)is mixed to a finished state in the interior of the cartridge 6 by meansof the vacuum mixing device, the cartridge 6 can thus be unscrewed fromthe housing 19, and a dispensing pipe (not shown) can be screwed intothe internal thread 14, through which pipe the finished bone cementdough 96 (see FIG. 8) can be driven out by advancing the dispensingplunger 8 in the direction of the internal thread 14. A static mixer canbe provided in the dispensing pipe, which mixer provides an additionalmixing of the bone cement dough 96.

The two-part dispensing plunger 8 has a sealing plunger 20 and asterilisation plunger 22. The sterilisation plunger 22 has a membrane orpore plate 24, which is permeable for a sterilising gas, but is notpermeable for the cement powder 9. The sterilisation plunger 22 isinserted into the cartridge 6 once the cement powder 9 has been filledtherein and closes the interior of the cartridge 6 with respect to theoutside. The content in the cartridge 6 can then be sterilised withethylene dioxide through the gas-permeable membrane or pore plate 24.

This sealing plunger 20 can be pushed into the sterilisation plunger 22and can be connected thereto in a gas-tight and pressure-tight manner.The plunger parts 20, 22 secured to one another then together form thedispensing plunger 8, by means of which the content in the cartridge 6can be pressed out through the opening in the connection piece havingthe internal thread 14. The sterilisation plunger 22 is initially lockedon the side opposite the side with the opening in the connection piecehaving the internal thread 14 (at the top in FIGS. 3, 4 and 6 to 8),wherein the locking is releasable. As a result of the locking, thesterilisation plunger 22 is prevented from moving undesirably during thesterilisation of the interior of the cartridge 6 and also the cementpowder 9.

The mixing blades 10 inside the cartridge 6, i.e. in the interior of thecartridge 6, are rotatable via the mixing shaft 12 or the cable 12 andare movable in the longitudinal direction of the cartridge 6.

A feedthrough is provided in the sealing plunger 20, which feedthroughis connected to a connection line 26 in the form of a flexible vacuumline 26. This sealing plunger 20 is otherwise closed in a pressure-tightmanner with the cartridge 6. The vacuum line 26 opens via a first checkvalve 27 into the pump 3, such that only a flow in the direction intothe pump 3 is possible. The pump 3 is additionally connected to thesurroundings via a second check valve 28, such that an overpressurecreated in the pump 3 can be discharged via the second check valve 28.Details regarding the check valves 27, 28 are illustrated in FIG. 5 andwill be described further below in the description. A filter (not shown)can be provided optionally at the second check valve 28, by means ofwhich filter methacrylate vapours or other disruptive chemicalsubstances can be filtered out from the gas flowing out.

The pump 3 has a stable hollow cylinder 29. The hollow cylinder 29 isseparated in a pressure-tight manner into two parts via a plunger 30.For this purpose, the plunger 30 has a peripheral seal 32, whichterminates with the inner wall of the hollow cylinder 29. The plunger 30is connected to a cable 34 or a flexible rod 34 made of a stableresilient plastics material or made of a metal, such as steel, whichleads through a feedthrough in a rear-side closure 33. On the frontside, the pump 3 is closed by a front-side closure, in which there aredisposed the connections for the check valves 27, 28. The closure 33 isconnected on the sides of the hollow cylinder 29 opposite the checkvalves 27, 28. The vacuum line 26 is guided as far as the pump 3, suchthat the feedthrough in the sealing plunger 20 is connected in apressure-tight manner via the vacuum line 26 to the pump 3, morespecifically to a pump chamber 94 (see FIG. 8) of the pump 3. The pumpchamber 94 is delimited by the inner walls of the hollow cylinder 29, bythe front-side closure, and by the plunger 30.

The cable 34 is connected to a detent means 36, which can latch with amating detent means 38 (see FIGS. 7 and 8). The mating detent means 38is part of the operating element 4, which is constructed as a lever 4which can be rotated or pivoted about an axis 40. The lever 4 comprisestwo lever arms 41, 42, which extend from the axis 40 in differentdirections. The actual operating part of the lever 4 is formed by thefirst lever arm 41, which ends in a handle 44, which can be manuallyoperated from outside. The first lever arm 41 thus protrudes out fromthe housing 19, and the handle 44 is arranged outside the housing 19 andcan be manually operated by the user of the vacuum mixing device. Here,a considerable force can be transferred into the interior of the vacuummixing device via the first lever arm 41 and is sufficient and is usedin accordance with the invention to drive the opening device 5, the pump3, and the mixing device 10.

The second lever arm 42, as the lever 4 is pivoted or as the lever 4 ispushed down, pushes against the opening device 5 and drives this. Forthis purpose, the opening device 5 is constructed with a lever 46, whichis mounted so as to be rotatable or pivotable about an axis 47. At theend of the lever 46 opposite the axis 47, an insert having an edge 48 isprovided, which bears against the receptacle 2 or the liquid container2.

The liquid container 2 or the receptacle 2 comprises an inner resilientinsert 50, which for example can consist of a rubber, and a rigid hollowcylinder 52 made of a plastics material, such as plastic. A glassampoule 54 containing a monomer liquid is inserted into the receptacle 2or the liquid container 2. The monomer liquid forms a bone cement dough96 together with the cement powder 9 from the cartridge 6 when these aremixed together. The inner walls of the resilient insert 50 bear againstthe glass ampoule 54. The glass ampoule 54 has an ampoule head 56 and anampoule base 58 opposite the ampoule head 56. The glass ampoule 54 sitsvia the ampoule base 58 on a support 60, which is formed as a shoulder60 of the resilient insert 50. At the upper side, a hollow cylinder 62made of a gas-permeable foam material and which is secured to the innerside of the housing 19 pushes the glass ampoule 54 against the support60. Openings are provided between the hollow cylinder 52 and the housing19, through which openings air or gas from the surroundings of thereceptacle 2 and the vacuum mixing device can flow into the receptacle2. The monomer liquid can thus flow out from the receptacle 2 moreeasily. The openings between the hollow cylinder 52 and the housing 19are formed in such a way that they are arranged in the lateral cylinderwall of the hollow cylinder 52 in a manner bordering the upper base areaof the hollow cylinder 52. The hollow cylinder 52 thus bears only inregions against the housing 19. Air can flow therebetween into theinterior of the receptacle 2.

In the region of the ampoule base 58 or the support 60, the hollowcylinder 52 has a recess, within which the edge 48 bears against theresilient insert 50, such that the ampoule base 58 is broken open by theopening device 5 and therefore the glass ampoule 54 can be opened. Theampoule head 56 of the glass ampoule 54 is usually broken open in orderto open the glass ampoule 54. Since the glass ampoule 54 is thin at theneck, this means that the monomer liquid can run out only slowly fromthe glass ampoule 54 and therefore the user must wait until they canperform the next steps for operating the vacuum mixing device. This isnot suitable in the case of the largely automated method, which isdriven by operation of the lever 4 or the operating element 4, since itis not possible to ensure that the monomer liquid from the glass ampoule54 will be available yet when the pump 3 is driven via the operatingelement 4.

The glass ampoule 54 pushes into the insert 50 made of the deformablematerial. The insert 50 together with the hollow cylinder 52 forms theessential parts of the receptacle 2 for the glass ampoule 54. The glassampoule 54 can be pushed into the insert 50 of the liquid container 2only as far as the ampoule base 58 on account of the shoulder 60.

The liquid container 2 has a lateral opening, in which the insert 50forms a deformable side wall. At this point, the glass ampoule 54 can beopened or broken open by application of a pressure onto the glassampoule 54 by the deformable side wall 50 just above the ampoule base58. When the ampoule base 58 of the glass ampoule 54 is broken open orthe glass ampoule 54 is opened, the monomer liquid can flow out from theopen glass ampoule 54 over the entire cross-section, such that themonomer liquid is quickly available in its entirety for furtherprocessing within the vacuum mixing device.

In order to deform the deformable side wall 50 and thus break open theglass ampoule 54, the lever 42 is used, which can be operated via thelever 4 and which can be rotated about the axis 40. The lever 4 ismounted pivotably or rotatably about the axis 40 relative to the housing19. The axis 40 divides the lever 4 into a long lever arm 41, to whichthe handle 44 is secured, and a short lever arm 42, which is arrangedinside the housing 19. At the start, the long lever arm 41 can only bemoved away from the liquid container 2 and not towards said container,since the long lever arm 41 bears at the top against the opening of thehousing 19 and thus prevents a further movement in this direction.

The short lever arm 42 of the lever 4 bears on its side facing towardsthe liquid container 2 against the lever 46 of the opening device 5,which is connected to the base part 18 or the housing 19 of the vacuummixing device via a joint 47 or the axis 47 in a manner rotatable aboutthe axis 47. This lever 46 of the opening device 5 is arranged insidethe housing 19. The free lever end of the lever 46 in the housing 19 ismovable by means of the short lever arm 42. At the tip of the free leverend, the edge 48 is secured and bears against the deformable side wall5. The axis 47 of the lever 46 is arranged here such that the free leverarm and therefore the edge 48 moves in the direction of the deformableside wall 5 and in the direction of the base part 18. The force that canbe exerted from the edge 48 through the deformable side wall 50 onto theglass ampoule 54 thus also pushes the glass ampoule 54 lightly in thedirection of the shoulder 60 and thus presses the glass ampoule 50 intothe receptacle 2.

A sieve 64 and/or a filter 64 are/is arranged below the shoulder 60, bymeans of which sieve and/or filter glass splinters of the opened orbroken-open glass ampoule 54 are held back. The distance between theshoulder 60 and the sieve 64 and/or filter 64 is greater than the outerdiameter of the glass ampoule 54, such that the dropping ampoule base 58can rotate in the gap and the flow of monomer liquid from the openedglass ampoule 54 is not hindered (see FIGS. 6 to 8). The monomer liquidthen remains at least in part in a storage volume 66, which is arrangedbelow the glass ampoule 54 and in which the sieve 64 and/or the filter64 are/is arranged. A funnel 68 is arranged below the sieve 54 and/orfilter 64 and opens out into a fluid connection 70 or liquid line 70.

The front side of the cartridge 6 (at the bottom in FIGS. 1 to 4 and 6to 8) is tightly connected to the storage volume 66 or the funnel 68 ofthe liquid container 2 by the base part 18 and the housing 19 via thefluid connection 70. A loop 71 is provided in the fluid connection 70,by means of which a monomer liquid (not shown) contained in the liquidcontainer 2 or the storage volume 66 is prevented from being able toadvance undesirably into the interior of the cartridge 6.

The cartridge 6 is releasably secured perpendicularly on the housing 19.The fluid connection 70 opens out in the connection piece having theexternal thread 16 through a filter 72 impermeable to powder butpermeable for the monomer liquid into the interior of the cartridge 6.An annular channel 73 (denoted only in FIGS. 3 and 8, but also visiblein FIGS. 4, 6 and 7) is formed beneath the filter 72 and is open towardsthe filter 72, such that the filter 72, which is likewise annular,covers the annular channel. The annular channel 73, into which the fluidconnection 70 opens out and which strictly speaking also belongs to thefluid connection 70, and the annular filter 72 surround the passage inwhich the mixing shaft 12 or the cable 12 is guided in the interior ofthe cartridge 6. Seals (not shown) or at least scrapers (not shown) canbe provided in the passage for this purpose. As a result of the annularchannel 73, the monomer liquid is introduced through the filter 72around the mixing shaft 12 into the interior of the cartridge 6. Anozzle (not shown) can also be provided at the entry of the fluidconnection 70 into the interior of the cartridge 6, which nozzledistributes the monomer liquid in the interior or in the cement powder9.

The liquid container 2 is closed upwardly by means of the housing 19once the glass ampoule 54 has been inserted into the liquid container 2.So that the monomer liquid can run out or run off from the glass ampoule54 and the storage volume 66 without difficulty, a number of passages(not shown) can additionally be provided in the part of the housing 19covering the liquid container 2, through which air from outside can flowinto the liquid container 2. Once the glass ampoule 54 has been brokenopen, the monomer liquid is available in the storage volume 66 and thefluid connection 70 and can be conducted through the fluid connection 70into the interior of the cartridge 6, in which a negative pressure inthe interior of the cartridge 6 is used in order to suck the monomerliquid from the liquid container 2 into the interior of the cartridge 6.This negative pressure is generated by means of the pump 3. In theinterior of the cartridge 6, the monomer liquid can then be mixed withthe cement powder 9 with the aid of the mixing device 10 under vacuum orunder negative pressure in order to produce the bone cement 96 or a bonecement dough 96.

The mixing device 10 is used to mix the content in the interior of thecartridge 6. The cable 12 or the mixing shaft 12, via which the mixingdevice 10 is rotated in the interior and is moved up and down in thelongitudinal direction of the interior, is deflected via pins 74 ordeflection rollers 74 in the direction of a cylinder 76. The deflectionrollers 74 can be reconstructed with spring-mounted tubes or deflectionsleeves. Here, the springs serve merely to fix the deflection rollers 74or deflection sleeves. The cable 12 or the mixing shaft 12 is rigidlyconnected to the cylinder 76. The cylinder 76 has a steep externalthread 78 on the outer side. The cylinder 76 is arranged in a sleeve 80having an internal thread 82 matching the external thread 78. As thecylinder 76 is moved in the sleeve 80 in the longitudinal direction (ofthe cylinder axis), the mixing device 10 is thus moved via the cable 12or the mixing shaft 12 in the longitudinal direction of the interior ofthe cartridge 6 and at the same time is rotated about the mixing shaft12 on account of the threads 78, 82, and the content in the interior isthus mixed. Alternatively to the external thread 78 on the sleeve, oneor more protrusions or one or more lobes 78 can also be provided, whichrun in the internal thread 82 and thus rotate the cylinder 76 in thesleeve 80.

The cylinder 76 is connected via a ball joint or a ball joint head 84 toa rigid cable 86 or a flexible rod 86, which is constructed similarly tothe cable 34 or the flexible rod 34 for the pump 3. The ball joint head84 can thus move within a receptacle for the ball joint head 84 of thecylinder 76 and can rotate therein. It is thus made possible, as thecable 86 moves, for a rotation of the cylinder 76 in the sleeve 80 to beenforced at the same time. The cable 86, which is connected to thecylinder 76, and the cable 34, which is connected to the plunger 30 ofthe pump 3, are connected to one another, wherein both are positionedvia pins 88 or deflection rollers 88. The defection rollers 88 areconstructed similarly to the deflection rollers 74. The connection ofthe cable 34 to the plunger 30 can also be constructed by means of aball joint. The two cables 34, 86 or flexible rods 34, 86 are joinedtogether to form a cable 90 or a flexible rod 90 which is guidedupwardly to the lever 4 or to the operating element 4, wherein the cable90 or the flexible rod 90 ends there in the detent means 36. The cable90 is also constructed similarly to the cable 34 for the pump 3, or theflexible rod 90 is constructed similarly to the flexible rod 34 for thepump 3. The cables 34, 86, 90 connected in a forked manner or the forkedrods 34, 86, 90 can be produced from a plastics material by injectionmoulding, or the common forked cable 34, 86, 90 or the forked rod 34,86, 90 can be produced from a plastics material by injection moulding.The detent means 36 at the end of the cable 90 is mounted here andpretensioned such that it engages with the mating detent means 38 andlatches therewith when the lever 4 is rotated or pivoted or when themating detent means 38 is pivoted at the height of the detent means 36.

The maximum stroke, which is determined by a rounded portion on thelever 4 formed as an involute 83, the cable 90 or the flexible rod 90being brought up to the involute 83 following successful latching, issufficient for the mixing device 10 to be passed through the interior ofthe cartridge 6 over the entire length thereof. This can be seen inFIGS. 3, 4, 6 and 7 in comparison with FIG. 8, since with a completestroke of the lever 4, which is illustrated in FIG. 8, the mixing device10 or the mixing blades 10 bears/bear on the filter 72 at the front sideof the interior of the cartridge 6, whereas without stroke, asillustrated in FIG. 7, the mixing device 10 or the mixing blades 10bears/bear against the dispensing plunger 8 or the sterilisation plunger22 and the pore plate 24 on the rear side of the interior of thecartridge 6. A complete mixing of the interior of the cartridge 6 withthe mixing device 10 is thus made possible. The mating detent means 38is for this purpose arranged at the end of the involute 83 facing awayfrom the pulling direction of the cables 90, 34, 86 or the flexible rods90, 34, 86 so that the cable 90 or the flexible rod 90 can be brought upover a wide area of the involute 83.

Instead of connecting the cable 34 or other flexible rod 34 of the pump3 and the cable 86 or the flexible rod 86 of the cylinder 76 to oneanother to form the cable 90 or the flexible rod 90, on which the detentmeans 36 is arranged, each of the cables 34, 86 or each of the flexiblerods 34, 86 can just as easily have its own detent means, which engageswith the mating detent means 38 or the two different mating detent meansat the end of the involute 83 or the lever 4 and latches therewith.

In an alternative embodiment of a mixing device according to theinvention, the cable 12 can be directly connected to the cable 86, orthe two cables 12, 86 can be formed as a common continuous cable, or theflexible rod 12 can be formed in one part with the flexible rod 86. Thecylinder 76, the sleeve 80, and the threads 78, 82 are then superfluousand are not provided. This leads to the mixing device 10 no longer beingrotated by the mixing shaft 12 in the interior of the cartridge 6. Amixing of the interior of the cartridge 6 is then still achieved only bythe movement up and down of the mixing device 10 in the longitudinaldirection. By means of a suitable inclination of the mixing blades 10 orsome of the mixing blades 10 and/or by a guidance of at least oneprotrusion (not shown) on the mixing device 10 in at least one spiralledgroove (not shown) in the inner wall of the cartridge 6, a rotation ofthe mixing device 10 in the cartridge 6 can also be enforced in anotherway, provided the rotation of the mixing device 10 in the cartridge 6 isnot easily foregone.

FIG. 5 shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 4 and 6 to 8 with a plane of sectionperpendicular to the section in FIGS. 3 and 4 and 6 to 8. Inter alia, anexemplary construction of the check valves 27, 28 is explained herein.The check valves 27, 28 are constructed with balls 91, which are pushedby springs 92 onto a ball seat, in which the connection to the vacuumline 26 or to the surroundings of the pump 3 is disposed. When the balls91 are pushed onto the ball seat, these connections are closed. Thecheck valve 27 opens when a negative pressure relative to the pressurein the vacuum line 26 or relative to the interior of the cartridge 6 iscreated or provided in the pump 3 by moving the plunger 30 in thedirection of the closure 33, i.e. when the pump chamber 94 (see FIG. 8)opens. The check valve 28 by contrast opens when a pressure greater thanthat in the surroundings prevails in the pump chamber 94 or in the pump3. Otherwise, the check valves 27, 28 close on account of the springforce of the springs 92.

The vacuum mixing device is characterised in accordance with theinvention by the applicability of the following exemplary methodaccording to the invention. The monomer liquid is provided in the liquidcontainer 2 by breaking open the glass ampoule 54 by means of theopening device 5, as explained above. For this purpose, the lever 4,which is disposed originally in an upright position (see FIGS. 1 to 4)is pushed down (see FIG. 6). Whilst the monomer liquid runs out andfills the storage volume 66 and the fluid connection 70, without passingvia the loop 71, the lever 40 is rotated or pivoted further, until themating detent means 38 is rotated at the height of the detent means 36and both latch with one another (see FIG. 7). By means of the latchingof the detent means 36 with the mating detent means 38, the pump 3 cannow be moved or driven by means of the lever 4 via the cable 34, 90 orthe flexible rod 34, 90, and the mixing device 10 can be driven by meansof the lever 4 via the cable 86, 90 or the rod 86, 90, the cylinder 76,and the cable 12 or the mixing shaft 12. For this purpose, the lever 4is rotated or pivoted away from the lower stop, back into the startingposition (FIGS. 2 to 4).

The pump 3 is used in that the plunger 30 is drawn by means of theoperating element 4 via the cable 34, 90 or the flexible rod 34, 90 awayfrom the check valves 27, 28 in the direction of the closure 33. In sodoing, the pump chamber 94 inside the pump 3 opens (see FIG. 8). Due tothe enlargement of the pump chamber 94, a lower pressure is generated inthe pump chamber 94. This leads to an opening of the check valve 27, sothat gas is sucked or pushed from the interior of the cartridge 6,through the connection line 26, into the pump chamber 94. On account ofthe resultant negative pressure, the monomer liquid is sucked from thestorage volume 66, through the fluid connection 70, into the interior ofthe cartridge 6.

The plunger 30 is moved as far as the end of the hollow cylinder 29 (onthe right in FIGS. 3 to 4 and 6 to 8). This arrangement is shown in FIG.8. The volume increase of the pump chamber 96 can preferably besufficient to evacuate the gas from the vacuum line 26, the interior ofthe cartridge 6, and the fluid connection 70, and to draw the monomerliquid from the liquid container 2 into the interior of the cartridge 6,such that just one stroke of the plunger 30 is sufficient to transferthe monomer liquid into the interior of the cartridge 6. The expandedpump chamber 96 for this purpose can preferably be larger than thevolumes of the lines 26, 70, the interior of the cartridge 6, and theliquid volume of the monomer liquid. Due to the negative pressure in theinterior of the cartridge 6, the monomer liquid is sucked away from thereceptacle 2 or the storage volume 66, through the fluid connection 70,via the loop 71, into the interior of the cartridge 6. Alternatively tothe transfer of the monomer liquid by means of a single stroke of theplunger 30, however, the monomer liquid can also be sucked into theinterior of the cartridge 6 by means of a number of strokes of theplunger 30 by repeated operation of the lever 4 (pivoting of the lever 4to and fro).

The part of the interior of the hollow cylinder 29 between the frontclosure with the check valves 27, 28 thereon (on the left in FIGS. 3, 4and 6 to 8, and at the top in FIG. 5) and the plunger 30 forms the pumpchamber 94. A negative pressure in the pump chamber 94 can thus actthrough the vacuum line 26 into the interior of the cartridge 6, or agas can be evacuated from the interior of the cartridge 6 when thesealing plunger 20, as shown in the Figures, is connected to thesterilisation plunger 22 and the interior of the cartridge 6 is thussealed externally, apart from the opening to the vacuum line 26.

At the same time as the continued movement of the plunger 30, thecylinder 76 in the sleeve 80 is moved in the longitudinal direction viathe cable 86, 90 or the rod 86, 90 and the ball joint 84, and, in sodoing, is rotated via the threads 72, 82. The movement in thelongitudinal direction and the rotation is transferred via the mixingshaft 12 or the cable 12 through the feedthrough onto the mixing device10 in the interior of the cartridge 6. As a result of multiple pivotingof the lever 4 in both directions and thus movement of the mixing device10 in the interior of the cartridge 6, the content, specifically thebone cement powder 9 and the sucked-in monomer liquid, is mixed, therebyproducing a bone cement dough 96 in the interior of the cartridge 6.

When the starting components have been mixed in the interior of thecartridge 6 by means of the mixing blades 10, the cartridge system 1 isunscrewed from the housing 19 or the external thread 16 of the housing19, and the cable 12 or the mixing shaft 12 comprising the mixing device10 is removed from the interior of the cartridge 6. In so doing, themixing blades 10 collapse upwardly. For this purpose, tapered materialportions as predetermined bending points are provided at the point ofconnection of the mixing blades 10 to the mixing shaft 12.

The sealing plunger 20 is rotated relative to the sterilisation plunger22, and the gas feedthrough is thus closed by the sealing plunger 20.The vacuum line 26 is removed from the sealing plunger 20. Once thecartridge system 1 has been unscrewed, a dispensing pipe (not shown)having a matching external thread is screwed into the internal thread14, and the mixed bone cement 96 can be applied through said pipe. Theconveying plunger 8 or dispensing plunger 8 assembled from thesterilisation plunger 22 and the sealing plunger 20 is unlatched and canbe driven inside the cartridge 6 by means of an application device (notshown). The content in the cartridge 6, i.e. the bone cement dough 96mixed under negative pressure, is thus pressed out from the oppositeopening and through the screwed-on dispensing pipe.

The components of the vacuum mixing device, apart from the glass ampoule54, the filters 64, 72, and the starting components of the bone cement,can be produced from plastics material by injection moulding. The fluidconnection 70 can consist of another plastics material. The connectionline 26 can be flexible so as to be able to be removed more easily fromthe sealing plunger 20.

The lines 26, 70 and the cables 34, 86, 90 or the forked rod 34, 86, 90are arranged in the housing 19 made of plastics material, which isfixedly connected to the base part 18, wherein the base part 18 has aflat base so that the vacuum mixing device can be placed on a flatsubstrate.

Instead of the glass ampoule 54 used with the exemplary embodimentdescribed, another monomer liquid container can also be used. By way ofexample, a film bag containing the monomer liquid can be used ascontainer for the monomer liquid in a modified receptacle. The film bagby way of example can be a plastics material bag coated with aluminiumwhich is chemically sufficiently resistant to the monomer liquid. In thealternative receptacle 2, a mandrel or better still a blade can beprovided, which is to be pushed and moved against the film bag by meansof the opening device 5 so that the film bag is pierced or slit open bymeans of the mandrel or the blade via the opening device 5, such thatthe monomer liquid then runs out from the film bag and is available inthe receptacle 2. The container for the monomer liquid can also befixedly integrated in the receptacle 2 and therefore in the vacuummixing device and can be opened towards the filter 64 and/or sieve 64 ortowards the fluid connection 70 by means of the opening device 5.

The variant with glass ampoule 54 as container for the monomer liquid ispreferred, however, in accordance with the invention, since the glassampoules 54 filled with monomer liquid are commercially availableinexpensively and in addition glass ampoules 54 are particularly wellsuited for long-term storage of the monomer liquid. Here, it isparticularly preferred for the glass ampoule 54 to be contained alreadyin the receptacle 2 of the vacuum mixing device.

With the described vacuum mixing device, the two starting components ofthe bone cement can be stored and mixed at any later moment in timeunder vacuum. Here, the vacuum mixing device does not have to beconnected to an external supply (power, water or compressed gas). Thereis no need for an internal energy store, such as a battery, a compressedgas cartridge or a tension spring, for driving the vacuum mixing deviceor the pump 3, the mixing device 10, and the opening device 5. Theenergy necessary to generate the negative pressure is also appliedmanually, such as the force necessary to open the glass ampoule 54 andthe force necessary to move the mixing device 10.

The features of the invention disclosed in the above description and inthe claims, Figures and exemplary embodiments can be essential, bothindividually and in any combination, for the implementation of theinvention in its various embodiments.

LIST OF REFERENCE SIGNS

-   1 cartridge system-   2 receptacle-   3 pump-   4 operating element/lever-   5 opening device-   6 cartridge/cartridge wall/hollow cylinder-   8 dispensing plunger-   9 cement powder-   10 mixing device/mixing blades-   12 mixing shaft/cable-   14 internal thread-   16 external thread-   18 base part/stand-   19 housing-   20 sealing plunger-   22 sterilisation plunger-   24 pore plate-   26 connection line/vacuum line-   27 check valve-   28 check valve/exhaust air-   29 hollow cylinder-   30 plunger-   32 seal/O-ring-   33 closure-   34 cable/flexible rod-   36 detent means-   38 mating detent means-   40 axis-   41 lever arm-   42 lever arm-   44 handle-   46 lever-   47 axis-   48 edge-   50 resilient insert-   52 hollow cylinder-   54 glass ampoule with monomer liquid-   56 ampoule head-   58 ampoule base-   60 support/shoulder-   62 hollow cylinder-   64 filter/sieve-   66 storage volume-   68 funnel-   70 fluid connection/liquid line-   71 loop-   72 powder-impermeable and liquid-permeable filter-   73 annular channel-   74 pin/deflection roller-   76 cylinder-   78 external thread/lobe-   80 sleeve-   82 internal thread-   83 involute-   84 ball-joint head-   86 cable/flexible rod-   88 pin/deflection roller-   90 cable/flexible rod-   91 ball-   92 spring-   94 pump chamber-   96 bone cement dough

We claim:
 1. A vacuum mixing device for mixing polymethylmethacrylate bone cement from a monomer liquid and a cement powder, the vacuum mixing device comprising at least one cartridge comprising an evacuable interior for mixing of the bone cement, a mixing device for mixing the content in the interior of the at least one cartridge, which is arranged movably in the interior, a receptacle for receiving a separate container containing the monomer liquid or comprising an integrated container containing the monomer liquid, an opening device, that is arranged in the region of the receptacle in a manner movable relative to the receptacle such that, by moving the opening device, a separate container arranged in the receptacle is openable by means of the opening device, or the opening device is arranged in the region of the integrated container in a manner movable relative to the integrated container so that, by moving the opening device, the integrated container is openable by means of the opening device, a pump, in which a movable plunger for generating a negative pressure is arranged and delimits a pump chamber of the pump, and a connection line, which connects the interior of the at least one cartridge to the pump chamber of the pump, wherein the vacuum mixing system comprises an operating element that is operatable from outside, wherein the plunger in the pump is movable manually by means of the operating element, and further wherein the opening device is movable relative to the receptacle or relative to the integrated container by means of the same operating element, and the mixing device in the interior of the cartridge is movable by means of the same operating element in order to mix the content in the interior of the cartridge.
 2. The vacuum mixing device according to claim 1, wherein the operating element is connected, or is connectable, to the plunger such that the plunger is movable manually in the pump by operation of the operating element.
 3. The vacuum mixing device according to claim 1, wherein the receptacle, at least in regions, has closed side walls for receiving a glass ampoule as separate container, wherein the receptacle has at least one deformable closed side wall and a supporting element is provided opposite the deformable side wall, wherein the opening device is pressable via the operating element against the deformable side wall of the receptacle so that the deformable side wall deforms such that a matching glass ampoule arranged in the receptacle can be broken open by means of the opening device.
 4. The vacuum mixing device according to claim 1, wherein the opening device has a first lever which is mounted rotatably about a first axis in relation to the receptacle or the integrated container, wherein a free end of the first lever is pushable against a deformable side wall of the receptacle or the integrated container, wherein the operating element is formed by a second lever, which is mounted rotatably about a second axis in relation to the receptacle or the integrated container, wherein the second axis divides the second lever into a short lever arm and a long lever arm, wherein an end of the short lever arm is to be pushed by manual operation of the long lever arm against the first lever so that the free end of the first lever pushes against the deformable side wall and deforms this in such a way that a separate container disposed in the receptacle is openable, or pushes the first end of the first lever against the integrated container so that the integrated container opens towards a fluid connection.
 5. The vacuum mixing device according to claim 1, wherein the operating element is manually movable about an axis, wherein the operating element (4) is operatively connected to or is to be brought into operative connection with the opening device, the pump, and the mixing device such that a first operation of the operating element, and with a further operation of the operating element, the plunger in the pump is to be driven, and the mixing device in the interior is to be driven.
 6. The vacuum mixing device according to claim 5, wherein the plunger of the pump and/or the mixing device are/is to be driven via a flexible cable and/or a rod, wherein a detent means is provided on the flexible cable and/or the rod and after first-time operation of the operating element engages with a mating detent means on the operating element or with a mating detent means connected to the operating element so that, with operation of the operating element subsequent to the latching, the plunger of the pump and/or the mixing device are/is to be driven via the cable and/or the rod by means of the operating element.
 7. The vacuum mixing device according to claim 1, wherein the mixing device is axially movable in the interior in the longitudinal direction by operation of the operating element.
 8. The vacuum mixing device according to claim 1, wherein the mixing device is rotatable about the longitudinal axis of the interior by operation of the operating element, wherein for this purpose a cylinder connected to the mixing device and having an external thread moves in a stationary sleeve having a matching internal thread so that, when the cylinder moves along the longitudinal direction within the sleeve, a rotation of the cylinder is enforced, wherein the rotation of the cylinder transfers to the mixing device in the interior of the cartridge.
 9. The vacuum mixing device according to claim 1, wherein the pump chamber of the pump is gas-tight and is arranged in the interior of the pump, wherein the plunger is manually drivable via the operating element in at least one direction, such that the pump chamber is to be enlarged by the movement of the plunger and the interior of the at least one cartridge is to be evacuable through the connection line by means of the resultant negative pressure created in the pump chamber.
 10. The vacuum mixing device according to claim 1, wherein a first one-way valve is arranged in the connection from the pump chamber to the connection line or in the connection line, which first one-way valve is open or is actively opened when a pressure lower than in the interior of the cartridge prevails in the pump chamber and is in a closed state or is actively closed when a pressure equal to or higher than in the interior of the cartridge prevails in the pump chamber, and a second one-way valve connects the pump chamber to the surroundings of the pump, which second one-way valve is open or is actively opened when a pressure higher than in the surroundings of the pump prevails in the pump chamber and is in the closed state or is actively closed when a pressure equal to or lower than in the surroundings of the pump prevails in the pump chamber.
 11. The vacuum mixing device according to claim 1, wherein the plunger is mounted axially movably in a hollow cylinder, wherein the hollow cylinder is closed on a first side or is closed apart from a feedthrough for a rod or cable connected to the operating element and the plunger, in particular is closed by a closure, wherein a pump chamber is formed in the hollow cylinder between the plunger and the first closed side, wherein the hollow cylinder is open on a second side.
 12. The vacuum mixing device according to claim 1, wherein the plunger is connected or is connectable via a rod and/or a cable to the operating element, and the plunger preferably is to be moved in the pump by operation of the operating element.
 13. The vacuum mixing device according to claim 1, wherein a movable dispensing plunger for discharging the mixed bone cement from the cartridge is arranged in the interior of the cartridge, wherein the dispensing plunger is preferably releasably locked or is lockable in order to prevent a movement of the dispensing plunger under the action of the negative pressure.
 14. The vacuum mixing device according to claim 1, wherein the cartridge is a cement cartridge filled with cement powder and a separate container containing a monomer liquid is arranged in the receptacle or a monomer liquid is contained in the integrated container, wherein the receptacle or the integrated container is preferably connected in a liquid-impermeable manner to the interior of the cement cartridge by means of a separating element that is to be opened and/or the interior of the cement cartridge is connected or connectable in a gas-permeable manner to the pump.
 15. The vacuum mixing device according to claim 1, wherein the cartridge, the pump, and all lines and also the receptacle or the integrated container are fixedly and/or releasably connected to a common base part and/or a housing, wherein the pump and all lines as well as the receptacle or the separate container are preferably fixedly connected to the base part and/or a housing and the cartridge is releasably connected to the base part and/or a housing.
 16. The vacuum mixing device according to claim 1, wherein the separate container containing the monomer liquid is a film bag which can be cut open or torn open in the receptacle by means of the opening device, or is a glass ampoule which can be broken open in the receptacle by means of the opening device.
 17. The vacuum mixing device according to claim 1, wherein the receptacle or the integrated container is connected or connectable via a fluid connection to the interior of the cartridge, wherein the mouth of the fluid connection into the interior of the cartridge is arranged on the opposite side of the mouth of the connection line between the interior and the pump chamber.
 18. The vacuum mixing device according to claim 17, wherein a loop is arranged in the fluid connection, such that the monomer liquid running out from the opened separate container or the integrated container cannot flow into the interior of the cartridge without negative pressure in the interior of the cartridge, wherein a storage volume for receiving the liquid volume of the monomer liquid is preferably arranged below the receptacle or the integrated container.
 19. The vacuum mixing device according to claim 1, wherein a negative pressure is to be generated in the pump chamber as a result of the movement of the plunger in the pump, wherein a gas is evacuable through the connection line from the interior of the at least one cartridge by means of the negative pressure.
 20. The vacuum mixing device according to claim 1, wherein the pump is constructed with a hollow cylinder, wherein the hollow cylinder is connected or connectable to the interior of the cartridge, a gas-tight closure at one hollow cylinder end, the plunger, which is arranged in the hollow cylinder in a gas-tight and actually movable manner, wherein the plunger in the pump is movable by means of the manually operable operating element, wherein with a movement of the plunger by means of the manually operable operating element, the plunger is movable axially oppositely to the closure and gas can thus be evacuated from the interior of the cartridge, wherein, the operating element is operatively connected to the opening device, and wherein the operating element is connected to the mixing device in the interior of the cartridge in such a way that the mixing device in the interior of the cartridge is movable with operation of the operating element.
 21. The vacuum mixing device according to claim 1, wherein the pump, the opening device, and the mixing device are drivable via the movement of the operating element, wherein the operating element is preferably moved by the action of manual force.
 22. A method for mixing polymethylmethacrylate bone cement in an interior of a cartridge of the vacuum mixing device according to claim 1, the method comprising: operating the operating element and an integrated container of the vacuum mixing device or a separate container, which is arranged in a receptacle of the vacuum mixing device, is thus opened, wherein a monomer liquid contained in the integrated container or the separate container then runs out as first component of the bone cement, by means of a subsequent, further operation of the operating element, a movement of a plunger of a pump of the vacuum mixing device is driven, wherein a negative pressure is generated in a pump chamber of the pump by means of the movement of the plunger, wherein the interior of the cartridge is evacuated by means of the pump driven in this way and the monomer liquid is conducted into the interior of the cartridge by means of the negative pressure in the interior of the cartridge, wherein a bone cement powder as second component of the bone cement is already disposed in the interior of the cartridge; and moving a mixing device in the interior of the cartridge is moved as a result of the operation of the operating element and a bone cement dough in the interior of the cartridge formed from the cement powder and the monomer liquid is mixed as a result of the movement of the mixing device.
 23. The method according to claim 22, wherein the volume of a pump chamber of the pump is increased by the manual movement of the plunger and the interior of the cartridge is evacuated due to the negative pressure created as a result.
 24. The method according to claim 22, wherein the plunger of the pump is moved by means of the operating element, whereby a negative pressure relative to the surrounding atmosphere is generated in the pump, in so doing gas from the interior of the cartridge is sucked into the pump chamber of the pump through a connection line, and the mixing device in the interior of the cartridge is then moved by operation of the same operating element, and in so doing the cement powder is mixed with the monomer liquid, the cartridge containing the mixed cement dough is then removed, and the cement dough is pressed out from the cartridge by means of an axial movement of a dispensing plunger.
 25. The method according to claim 22, wherein the cement powder is arranged in the cartridge, the monomer liquid is arranged in a receptacle separate from the cartridge, wherein the monomer liquid is contained in an integrated container or in a separate container, preferably in a glass ampoule in the receptacle, the integrated container or the separate container is opened by operation of the operating element and a resultant movement of the opening device, before the plunger is driven by a further operation of the operating element, the plunger is then moved axially in a hollow cylinder, whereby a negative pressure compared to the surrounding atmosphere is generated, in so doing gas from the interior of the cartridge is sucked through the connection line into the hollow cylinder, and monomer liquid is sucked into the cartridge by means of the negative pressure formed in the interior of the cartridge. 